Elimination of the Stray Grain Defects of Single Crystal Blade by Variable Wall Thickness Based on Integral Ceramic Mold

The stray grain defect is often found at the platform in the process of directional solidification of single crystal blades because local undercooling easily occurs in this area. A variable wall thickness mold based on stereolithography and gelcasting technology was proposed to solve the local undercooling at the platform. The influence of variable wall thickness mold on the temperature field of the platform during directional solidification was studied via simulation. The numerical simulation results show that variable wall thickness can effectively prevent heat dissipation at the platform, thereby reducing the undercooling and avoiding the formation of stray grains. At the same time, the influence of molds assembly angle on the formation of stray grains was analyzed, and the appropriate molds assembly angle is suggested.